Azo-dyestuffs



Patented Jan. 22, 1952 AZO-DYESTUFFS Max Schmid, Riehen, and Eduard Moser, Basel,-

Switzerland, assignors to Ciba Limited, Basel,

Switzerland, a Swiss firm No Drawing. Application July 20, 1948, Serial No.

33,809. In Switzerland December 19, 1944 wherein X is a nitrogen-containing substituent with a nitrogen atom directly attached to the ring carbon atom of the naphthalene nucleus. The centrally symmetrical positions of the azo-group (ii-position) and the nitrogen atom in 2-position appear to have certain eifects on the behavior of the Whole group of J-acid dyestuffs.

6 Claims. (01. 260- 166) According o the present invention valuable tetrakisazo-dyestuffs are made by coupling with one molecular proportion of 5 :5'-dihydroxy-2 :2- dinaphthylamine-7 :7-disu1fonic acid, one molecular proportion of a diazotized monoazo-dyestufi which is free from sulfonic acid groups and corresponds to the formula OOOH wherein R1 stands for an aromatic radical of the benzene series which is substituted by a hydroxyl and a carboxyl group in ortho position to each other, and R2 stands for an aromatic radical of the benzene series in which the groups NzN- and NH2 are in para-position to each other and which contains in ortho-position to the NHzgroup a group capable of taking part in the formation of metal complexes.

As monoazo-dyestuffs of the above general Formula I there are used, for example, ii-amino- 2 4' hydroxy-5'-methy1-1:1-azobenzene-3:3' dicarboxylic acid, 4-amino-4'-hydroxy-6'emethyl-@ 1 1 -azobenzene-3 :3'--dicarboxylic acid, 'l-a'mino- 2' hydroxy 5'-methoxy-l:l'-azobenzene-3:3'-r dicarboxylic acid, and, preferably, 4-amino-4fe hydroxy-l :1 '-azobenzene-3 3'-carb0xylic acid.

As monoazo-dyestufis of the above general Formula II there can be used, those which also correspond to the general Formula I and of which examples have already been given. Thus-valuable asymmetrical tetrakisazo-dyestufis can be made by coupling with 5:5'-dihydroxy-2:2'-dinaphthylamine-7 :7-disulfonic acid two different diazotized amino-monoazo-dyestufis eachof which corresponds to the general Formula I. Valuable symmetrical dyestufis are obtained by using two molecular proportions of the samecdiazotized amino-monoazo-dyestufi corresponding to Formula I.

Valuable asymmetrical tetrakisazodyestuffs can also be made by using as starting materials one molecular proportion of an amino-monoazodyestuif which corresponds to the general Formula I and one molecular proportion of an aml-.- no-monoazo-dyestufi which corresponds to the general Formula II but does not correspond to the general Formula I. As amino-monoazo-dyestuiIs of'this latter kind there come into con.- sideration, for example,- those of the above Formula II wherein R2 stands for an aromatic radical of the benzene series containing in orthoposition to the amino group an alkoxy group, preferably an alkoxy group containing only a few carbon atoms, such as an ethoxyor advantageously a methoxy group. The radical. R2 may carry either no substituents in addition to the groups N:N, -NH2 and alkoxy, or it may or a methoxy group).

contain, for example, in para-position to the alkoxygroup further substituents, such as an alkyl group (for instance a methyl group) or a further alkoxy group (for instance an ethoxy Thus, as monoazo-dyestufis of the general Formula II there can be used, for example: 4- amino-2-methy1 5 methoxy- 4'-hydroxy-l:l'.- azobenzene-3'-carboxylic acid; 4-amino3;-methoxy 4'-hydroxy 1:1-azobenzene-3'-carboxylic acid; 4 amino-2:5-dimethoxy-4'-hydroxy-1:1'-

azobenzene-3'-carboxylic acid; 4-amino-2-ethoxy-5-methoxy-4' hydroxy-l l-azobenzene-3.'- carboxylic acid; el-amino-Z-methoxy 5-ethoxy- 4' hydroxy-l :1'azobenzene-3-carboxylic acid; -amino 2 methyl-5-methoxy-4'-hydroxy-5- methyl-1 :1' -azobenzene-3'-carboxylic acid.

The monoazo-dyestuffs oi Formula I can be dyestufi into the amino group, for instance, by

means of an alkali sulfide.

The monoazo-dyestuffs of the Formula II of which the radical R2 contains in ortho-position to the amino-group an alkoxy group, can be prepared by coupling a diazotized amino-hydroxybenzene-ortho-carboxylic acid with an amine of the benzene series containing an alkoxy group in ortho-position to the amino group. Some of these ortho-alkoxy-aminobenzenes, such as ortho-methoxyor ortho-ethoxy-aminobenzene are coupled advantageously in the w-methane sulfonic acids.

The diazotizing of the amino-monoazo-dyestuffs of Formula I orII can be carried out advantageously by the ,so-called indirect method, viz. .by dissolving the amino-azo-dyestuff in dilute alkali, adding the calculated amount of an alkali nitrite and then uniting this solution with a dilute solution containing an excess of mineral "acid or a solution of sulfuric acid and naphthalene sulfonic acid.

7 In the present process coupling takes place with advantage in an alkaline medium. If symmetrical dyestuifs are to be made, the two mols of dia'zotized amino-monoazo-dyestuff may be united simultaneously with the solution rendered alkaline with an alkali hydroxide and containing one moi of 5:5'-dihydroxy-2:2'-dinaphthylamine-7z'7' -disulfonie acid. In the manufacture of asymmetriacl tetrakisazo-dyestuffs, coupling of the two different diazotized amino-monoazodyestuffs with the 5:5'-dihydroxy-2:2'-dinaphthylamine-I:'7-disulfonic acid may be carried out simultaneously but is effected with advantage in two different stages. Asymmetrical tetrakisazo-dyestuffs from one molecular proportion of a diazotized amino-monoazo-dyestufi of Formula I and one molecular proportion of a diazotized amino-monoazo-dyestuff of Formula II, wherein the Radical R2 contains an alkoxy group in ortho-position to the diazotized amino-group, are prepared advantageously by coupling first the diazotized amino-monoazo-dyestuff of Formula I with 5:5'-dihydroxy-2:2'-dinaphthylamine-'IzT-disulfonic acid in a rather weak alkaline medium, e. g. a medium alkaline with alkali carbonate, and then coupling the diazotized amino-monoazo-dyestuff of Formula II with the disazo-dyestufi thus obtained in a stronger alkaline medium, e. g. a medium alkaline COOE HO' OH form of their 7 These dyestuffs dye cellulose fibers such as cotton, linen or materials from regenerated cellulose, such as viscose or staple fiber chiefly reddish blue to greenish blue tints. Particularly valuable dyeings which are very fast to washing are obtained if the dyeings are after-treated with agents yielding copper.

The treatment of the cellulose fibers dyed with r the dyestuffs of the above composition in usual manner from a neutral or feebly alkaline bath, for instance alkaline with sodium carbonate, with agents yielding copper may be carried out with ordinary copper salts, such as copper sulfate,

in, a neutral or feebly acetic acid bath, or pref- 15 erably with copper compounds stable towards alkalies, such as are obtained for example by the reaction of ordinary copper salts with aliphatic hydroxy-earboxylic acids, such as tartaric acid, in an alkaline agent, for example an agent alkaline with alkali carbonate. Dyeing processes in which such coppering agents areused have been described for example in U. S. Patents 2,148,659 and 2,15,905. The treatment with the agents yielding copper may be eifected in the dyebath or in a fresh bath.

Especially'valuable dyeings can be obtained by working in accordance with the process in which dyeings or prints produced with the metalfree dyestuffs are after-treated with aqueous solutions which contain basic condensation products 'of. formaldehyde with compoundsv containing in the molecule at least once the atomic grouping or with compounds capable of being easily transformed into compounds containing said atomic grouping as, for instance, cyanamide, and which solutions also contain water-soluble copper compounds, especially complex copper compounds. Such processes are described, for example in British Patent No. 619,969.

As compared with the known dyestuffs of similar constitution which have been described in U. S. Patents 2,050,913 and 2,369,516 the new dyestuffs obtained according to the present process surprisingly yield coppered' dyeings of considerably better fastness to washing.

The following examples illustrate the invention, the parts and percentages being by Weight.

Example 1 30.1 parts of 4-amino-4-hydroxy-1:1'-azobenzene-3:3-dicarboxylic acid are dissolved with 27parts of sodium hydroxide solution of 30 per wherein R and R1 each stands for an aromatic cent. strength, in 200 parts of water and 7 parts radical of the benzene series which is substituted by a hydroxyl and a carboxyl group in ortho-position to each other and R2 stands for an aromatic radical of the benzene series in which the --N:N- groups are in para-position to each other and which contains a meta-position to the N:N.R1 radical a group capable of taking part in the formation of metal complexes, the radicals R, R1, and R2 being free from sulfonic acid groups.

solution of 10 per cent. strength, stirring is continued for another 2 hours and the precipitated dyestuff is filtered ofi and dried at a temperature of 100 C. It is a black powder of the formula O OH OH H Example 2 34.5 parts of the disodium salt of 4-amino-4'- hydroxy-l 1 -azobenzene-3 3 -dicarboxylic acid are dissolved in 300 parts of water and '7 parts of sodium nitrite are added. The solution is poured into a solution of 50 parts of hydrochloric acid following compounds: i-amino-3-methoxy-4'- hydroxy-i:1'-azobenzene-3-carboxylic acid, 4- amino 2:5 -dimethoxy-4'-hydroxy-l:l-azobenzene- 3'-carboxylic acid, 4-amino-2-e'thoxy-5- H O OH O OH methoxy 4' hydroxyl -1:1-azobenzene-3-carboxylic acid, 4-amino-2-methoxy-5-ethoxy-4- hydroxy-l:1-azobenzene-3'-carboxylic acid, 4- amino 2 methyl 5 methoxy 4'-hydroxy5'- methyl-1 1'-azobenzene-3'-carboxylic acid, 4-

amino 4 hydroxy-5'-methyl-1:l'-azobenzeneof 30 per cent., strength in 50 parts of water which has been cooled to 15 C. The whole is stirred for two hours and then the yellowish brown colored diazo paste is poured into a solution of 46.1 parts of 5:5 dihydroxy 2:2 dinaphthylamine-'lz'ldisulfonic acid in 300 parts of water and 40 parts of anhydrous sodium carbonate, which has been cooled to 5 C. When coupling is complete.the disazo-dyestuff is filtered ofirand dissolved in 230 parts of water with the addition of parts of sodium hydroxide and the solution is cooled to 0 0. Into this solution is poured a diazo paste which has been made from 30.1 parts of 4-amino-2-methyl-5-methoxy-4-hy droxy-l:1-azobenzene-3'carboxylic acid in accordance with the above prescription for diazotizing 4 amino-4-hydroxy-l:l'-azobenzene-3:3-

dicarboxylic acid and the whole is stirred for ,4 hours at 0-3" C. Then the excess of sodium hydroxide is neutralized with about 15 parts of hydrochloric acid of per cent. strength until the reaction mixture has but a slightly alkaline reaction to phenolphthalein paper. The tetrakis azo dyestufi is precipitated with sodium chloride,

filtered off and dried. It is a black powder which dissolves in water or dilute sodium hydroxide solution with a reddish blue coloration and in concentrated sulfuric acid with a green-blue coloration and which dyes cotton in accordance with the oneor two-bath after-coppering process reddish blue tints of very good fastness to washing. v p

Tetrakisazo-dyestuffs of similar properties are obtained by using as starting material instead of 4 amino 2-methyl-5-methoxy-4-hydroxy- 1:1'-azobenzene-3'-carboxylic acid one of the V is rinsed with cold water.

3 3-dicarboxylic acid.

Example 3 100 parts of cotton are entered at 50C. into a dyebath consisting of 4000 parts of water, 2 parts of anhydrous sodium carbonate and 1 part of the dyestuff obtainable as described in the first paragraph of Example 1, the temperature is raised to 90-95 C. in the course of 20 minutes, 30 parts of crystalline sodium sulfate are added, and dyeing is carried on for 30 minutes at 90-400 C. The whole is then allowed to cool to about C. and the further treatment consists of one of the procedures described under (a), (b) and (0) below.

(a) The dyeing is rinsed with cold water and treated for V hour at 50 C. in a bath containing 4000 parts of water, 3 parts of crystalline copper sulfate, and 1 part of acetic acid. The goods are then rinsed and dried A blue dyeing is obtained of good fastness to light and having very good properties of wet fastness.

(b) 4 parts of complex copper sodium tartrate of approximately neutral reaction are added to the dyebath cooled to about 70 C., coppering is carried on for hour at 0., and the dyeing If desired the dyeing may be soaped by after-treatment for hour in a bath containing, per liter, 5 grams of Marseilles soap and 2 grams of anhydrous sodium carbonate. A blue dyeing is obtained which has a good fastness to light and very good properties of wet fastness.

(c) The dyeing is rinsed with cold water, and then after-treated for hour at 20 C. in a solution, which has been prepared by dissolving 4.5 parts of the water-soluble condensation product of dicyandiamide and formaldehyde, 1.5 parts of copper acetate and 6 parts of concentrated aqueous ammonia solutionin 3000 parts of water and adding 2 parts of anhydrous sodium carbonate to the solution containing cupric tetramine: acetate. The goods are then rinsed and dried. There is obtained a blue dyeing which is distinguished by good fastness to light and very good properties of wet fastness.

What we claim is:

l. A tetrakisazo-dyestuif corresponding to the general formula 2,688,619 7 3 V whereinRandRieach stands for an aromatic 3.; The tetrakisazo-dyestufi corresponding to radical of the benzene series which is substituted the formula t x H035 NH SOaH H 7 00H 7 H v H 1100 I V OOH by a .hydroxyl and a carboxyl group in orthoposition to each other and R2 stands for a mono- 4 The tetrakisazo-dyestuff corresponding to nuclear aryl radical in which the N=N I5 the formula V groups are in para-position to each other and which contains in meta-position to the 5. The tetrakisazo-dyestufi corresponding to N=N-R1 the formula HO3S- NHi H00 7 l OOH HQ radical a substituent selected from the group 40 '6. A'tetrakisaz'o dyestuffs corresponding to the consisting of -COOH, -OCH3 and OCzI-Is, formula n H 035 NH O OH HO 1100( coon the radicals R, R1, and R2 being free from 'sul in which R2 stands for a mononuclear aryl radifonic acid groups. cal in which the N-N- groups are in para- 2. A tetrakisazo dyestuilf corresponding to the I 1 general formula v t 95 position to eachother and-which contains in in which R2 stands for a mononuclear aryl radimeta-position to the cal n Whlch the N=N- groups are m =para- N position to each other and which contains in meta-position to the O OH I radical an OCHs group, the radical R2 being 1 K free from sulfonic acid groups.

H OOH MAX SCI-IMID. radical 2. COOH group, the radical'Rz being v I EDUARD MOSER" free from sulfonie'acid groups. 15 (References 01': following page) REFERENCES CITED The following referenbes are of record In the file of this patent:

Number UNITED STATES PATENTS Name Date Gubler et a1. Nov. 25, 1930 Anderau Aug. 11, 1936 Kaiser Oct. 30, 1945 Kaiser Mar. 19, 1946 1Q Anderau Nov. 26, 1946 FOREIGN PATENTS Number Country Date 373,757 Ital Aug. 3, 1939 OTHER REFERENCES Groggins, "Unit Processes in Organic Syntheses, 1947, page 156. 

6. A TETRAKISAZO DYESTUFF CORRESPONDING TO THE FORMULA 